【作者】 林静；

【导师】 杨万勤； 张健；

【作者基本信息】 四川农业大学 ， 森林培育， 2008， 硕士

【摘要】 尽管有机氯农药（OCPs）已被禁用20多年,但以OCPs污染为主要特征的持久性有机污染物（POPs）在土壤和植物中的残留,仍在威胁着人类的生存与健康。迄今为止,有关OCPs残留和迁移特征的研究报道已经不计其数,但由于我国地形复杂、生态类型多样、农药的施用量和施用方式差异较大,从而使已有的研究还不能完全满足污染土壤修复和农林业清洁生产的需要。因此,以四川省典型的丘陵平原区（五通桥区）为研究对象,按功能分区和随机采样相结合的采集方法、Kriging插值法和模拟土柱实验相结合的研究方法,检测了93个表层土壤样品和215个植物样品（43个植物种类）的有机氯及其异构体代谢物含量,研究土壤中OCPs残留和迁移特征及其对土壤酶活性的影响,研究了该区主要植物的农药残留特征,评估了土壤中滴滴涕（DDTs）及其异构体残留特征和潜在的生态风险,初步筛选了吸收农药能力较强的植物和农药含量较少的植物,为该区农林业生产布局及污染土壤的生态修复提供科学依据。土壤中残留的HCHs和DDTs的异构体代谢物及总量均服从正态分布,并全部属于强变异。18.4%的土壤HCHs含量达到国家土壤环境质量一级标准(＜50μg·kg^-1),其余为二级标准(＜500μg·kg^-1);68.1%的土壤DDTs含量为国家土壤环境质量一级标准(＜50μg·kg^-1)。以农业和林业生产为主的区域（石麟镇）采集的土壤具有最高的α-HCH和β-HCH残留量;以农业生产为主的区域（冠英镇）采集的土壤具有最高的γ-HCH残留量,以人类活动频繁的区域（杨柳镇）采集的土壤具有最高的δ-HCH的残留量。以林业生产为主的区域（金山镇）采集的土壤p,p′-DDE和p,p′-DDD残留量很小;以人类活动频繁的区域（杨柳镇）采集的土壤p,p′-DDT的残留量最低。在不同的土地利用类型土壤中,OCPs总量的排序为水稻田＞农林间作地＞蔬菜地＞果园＞旱地＞苗圃地＞油菜地＞小麦轮作地,ΣHCH残留量由高到低的排序是农林间作地＞果园＞蔬菜地＞水稻田＞油菜地＞旱地＞苗圃地＞小麦轮作地:ΣDDT的大小排序为水稻田＞蔬菜地＞农林间作地＞果园＞苗圃地＞旱地＞小麦轮作地＞油菜地。土壤HCHs各代谢物含量呈块状分布,而HCHs总量相对较高的区域都分布在农业区（蔡金镇、冠英镇和石麟镇交界处）;DDT总量和p,p′-DDT含量的高值区域出现在低山丘陵区（石麟镇）;p,p′-DDD和p,p′-DDE含量的高值区域出现在平原区（杨柳镇、竹根镇和西坝镇）。总体而言,研究区域存在一定程度的有机氯农药污染。淋溶强度与OCPs的迁移降解成正向相关。土壤含水量为25.1%有利于0～10cm的钙质紫色土OCPs降解;土壤含水量为37.5%和26.8%不利于10～20cm的OCPs的降解。土壤含水量为42.3%和36.1%不利于0～10cm的酸性紫色土OCPs的降解;土壤含水量的增加不利于10～20cm的OCPs的降解。研究区土壤多酚氧化酶活性的增加可有利于土壤OCPs的降解。脱氢酶活性和脲酶活性对OCPs降解的影响不大。钙质紫色土OCPs的残留量减少,硝酸还原酶的活性也相应减少。研究区土壤都存在低剂量的DDTs潜在生态风险。其中,生活区和工业区的土壤具有潜在生态风险的可能性较小;农业区的土壤对鸟类,哺乳动物和土壤动物都可能具有潜在的风险。除小麦地和油菜地之外,其他土地利用类型对哺乳动物可能具有潜在的生态风险。研究的植物样品中,OCPs含量高的植物有马尾松（Pinus massonianalamb）(149.30μg.kg^-1)、芦苇（Phragmites communis）(112.99μg.kg^-1)、蕉芋（Canna edulis）(88.18μg.kg^-1)、甘薯（Ipomoea batatas）(75.90μg.kg^-1)和乌泡（Rubus multibracteatus）(999.43μg.kg^-1);含量低的植物有榕树（Firmiana simplex）(5.91μg.kg^-1)、南瓜（Cucurbitamoschata）(1.60μg.kg^-1)和柚（Citrus grandis）(1.44μg.kg^-1);紫云英（Astragalus sinicus）和三叶草（Medicago sativa）未检测出OCPs。农药残留量高的蕉芋、乌泡、山茶和小叶榕可能是很好的富集植物,紫云英、三叶草和血皮菜（Gynura pseudochinabicolor）可能为很好的排异植物。更多还原

【Abstract】 Persistent organic pollutants（POPs） characterized by organochlorine pesticides （OCPs） in the soil and plant residues remains the threats on the survival and health of human beings,although the pesticide has been prohibited over twenty years.Meanwhile, the results obtained in the past were still difficult to make the needs of polluted soil remediation and agricultural and forestry clean production resulting from the compex geomorph,diverse soils and ecological types,varied application methods and amounts of pesticide,although numerous studies have been given to the characteristics of residue and migration of OCPs.In order to provide the scientific basis with the optimal layout of agricultural and forestry clean production and polluted soil remediation,therefore,the contents of OCPs and their isomers and metabolites in 93 surface soils and 45 plants（215 plant samples） were detected in typical hilly and plain region（Wutongqiao County） of SW Sichuan,the characteristics of the residue and migration of OCPs in soils and its effect on soil enzyme activity were studied,the potential ecological risk was assessed,and the plants with higher and lower OCPs contents were distinguished based on the residual characteristics of OCPs in the representative plants,employing the methods of randomly sampling the soils according to functional zones and Kriging method in geostatistics in combination with simulated soil core experiment.Residual HCHs and DDTs and their isomers and metabolites in soils distributed normally with strong variations.HCHs concentration in 18.4%soils was lower than the first level of National Soil Environment Quality Standard（GB15618-1995）(＜50μg·kg^-1), and the rest the second level(＜500μg·kg^-1).Correspondingly,DDTs concentration in 68.1%soils were lower than 50μg·kg^-1,which accorded with the first level of National Soil Environment Quality Standard.Soils in the region（Shilin town） mainly with agricultural and forestry production had the highestα-HCH andβ-HCH contents,while soils in the region（Guanying town） mainly with agricultural production had the highestγ-HCH content.Similarly,soils from the region（Yangliu town） with the frequent human activities had the contents of the highestδ-HCH and the lowest p,p’-DDT,while soils from the region（Jinshan town） mainly with forestry production had the contents of lower p, p’-DDE and p,p’-DDD.The ranked order of the total OCPs content was rice fields＞agroforestry intercrop land＞vegetables land＞orchard land＞dry land＞nursery land＞rape land＞wheat rotate land,that ofΣHCH was agroforestry intercrop land＞orchard land＞vegetables land＞rice fields＞rape land＞dry land＞nursery land＞wheat rotate land, and that ofΣDDTwas rice fields＞vegetables land＞agroforestry intercrop land＞orchard land＞nursery land＞dry land＞wheat rotate land＞rape land.The contents of HCHs and their isomers and metabolites in soils distributed limpidly, while the total content of HCHs in soils were the highest in the agricultural zone（Caijin, Guanying and Shilin towns）.The hilly region（Shilin town） had the highest contents of total DDT and p,p’-DDT,while the basin plain（Yangliu,Zhugen and Xiba towns） had the highest contents of p,p’-DDD and p,p’-DDE in soils.On the whole,scils in the studied region were contaminated to a certain extent by residual organochlorine pesticide.The transfer and degradation of OCPs correlated positively and significantly with the eluviation intensity.0～10cm soil layers had higher OCPs degradation rate when soil moisture was 25.1%in calcareous purple soil,while higher soil moisture was not favorable for OCPs degradation.Similarly,0～10cm soil layers had higher OCPs degradation rate when soil moisture was 29.9%in acid purple soil,while higher soil moisture was not favorable for OCPs degradation.PPO activity correlated was favorable for OCPs degradation in soils.However,OCPs degradation was not significantly correlated with the activities of dehydrogenase and urease in soils.In addition,residual OCPs were positively and significantly correlated with the positive correlation with nitrate reductase activity in calcium purple soil.Soils in the study area had the low-dose potential ecological risks of DDTs.Soils in the zones of residence and industry had the lower potential ecological risks,while agricultural zone might have the higher potential risks to birds,mammals and soil animals. In addition to wheat and rapeseed,other land use types may have the potential ecological risks of mammals.Soils in other land uses had the potential ecological risks to mammals to a certain extent expect for wheat and rape fields.The plants with higher contents of organochlorine pesticide included Pinus massoniana,Phragmites communis,Canna edulis,Ipomoea batatas and Rubus multibracteatus,and the contents were 149.30μg·kg^-1,112.99μg·kg^-1,88.18μg·kg^-1,75.90μg·kg^-1,and 999.43μg·kg^-1,respectively.The plants lower contents of organophosphorus pesticide included Firmiana simplex,Cucurbita moschata and Citrus grandis had,and the contents were 5.91μg·kg^-1,1.60μg·kg^-1,and 1.44μg·kg^-1,respectively.The organochlorine pesticide in Astragalus sinicus and Medicago sativa had not been detected. Organophosphorus pesticide had lower contents in all plants,only the plants of Eucalyptus grandis(31.22μg·kg^-1),Metasequoia glyptostnobcides(6.45μg·kg^-1),Artemisia annua (43.23μg·kg^-1),Ipomoea batata(1.70μg·kg^-1),Apium graveolens(22.90μg·kg^-1),Glycine max Merr(49.57μg·kg^-1) and Ficus microcarpa(4.95μg·kg^-1) had been detected.It was suggested that Canna edulis,Rubus multibracteatus,Camellia japomica and Ficus micro Carpa be good accumulator plants for pesticides,and Astragalus sinicus,Medicago sativa, Gynura pseudochinabicolor be good non-accumulator plants for pesticides.更多还原